Opinion | What if we could wipe out all infectious diseases?4 min read . Updated: 20 Feb 2020, 10:33 PM IST
If infectious diseases are wiped out, chances are that we would still be faced with a miserable, costly and painful end to our lives, as there would be other illnesses waiting to kill us.
In the 1980s, when HIV was emergent, panic was in the air. HIV was particularly terrifying because it spread through a beloved human activity—sex—and killed brutally after years of stigma and suffering.
A chilling document from the United Nations Development Programme in the 1990s predicted the bleakest of all futures for mankind if HIV wasn’t checked. Young and able-bodied men would die off, depleting workforces and crippling economies, while governments would collapse as their leaders died of AIDS. Unless HIV was checked, the argument went, country after country would be wiped out, and we would see the end of civilization.
Whenever a new disease emerges, it stokes the same fear. What if this virus rages like a California wildfire, unchecked and uncheckable, until every human being is dead? Covid-19 had infected 75,777 people as of 20 February and killed 2,130. The world is wondering, once again if this will turn out to be the disease that ends all diseases.
Yet, 40 years after HIV burst on the scene, the percentage of people infected with it has remained more or less steady, levelling off at 0.8% in 2000, and not changing much since then. About 41.5 million people are infected with HIV today, up from 31.7 million in 2010; this corresponds to an increase in world population from 6.9 billion to 7.8 billion during the same period.
Theodore Modis would be very happy.
Modis is a futurist, physicist and founder of a consulting firm called Growth Dynamics. In his provocative 1992 book Predictions, he found overwhelmingly that most phenomena, both in nature and outside it, behaved like living organisms—growing, competing, maturing, weakening with age and dying. This applied to whether you were talking about crime rates, stock exchange fluctuations, democracy, wine harvests, or new diseases. Growth and decline typically followed an S-curve—starting slow, growing slowly, reaching a tipping point and then climbing steeply before plateauing out. The epiphany was that everything eventually levels out.
Modis tracked the known number of deaths caused in the early 1900s by diphtheria, one of the world’s big killers then, and found what he expected—an S-shaped curve just beginning to flatten out at the top. By 1933, when the diphtheria vaccine was officially approved, the disease was on its way out. It’s fair to wonder if the disease would have settled into a stable prevalence, just like HIV has, even without a vaccine.
Think of it as a “share of death". A certain number of people will die every year, either of a non-communicable disease (NCD), such as cancer, diabetes or heart disease, or an infectious disease such as malaria, typhoid, HIV or influenza. The perspective changes dramatically once you start considering viruses, bacteria, bacilli and other disease-causing organisms as just other creatures competing to survive on the same planet with finite resources, along with animals, birds, fish and humans.
Some are better at it than others. Human beings are a particularly rapacious form of life, willing to decimate entire species to meet their own needs. The two deadliest killers on the planet in 2016 were mosquitoes (780,000 deaths) and human beings (546,000 deaths).
Two things stand out: No disease has ever eliminated an entire species, and death is always shared among several diseases. At any given time, some 5-8 infectious diseases dominate the share of death. In 2017, it was tuberculosis (TB) among 15-69 year olds (429,672 deaths), with lower respiratory diseases like flu in second place with 405,835 deaths, and diarrhoeal diseases (239,089) next.
A person who dies of malaria today will not die of cancer tomorrow. If one disease increases its share of death, another takes a hit.
Here’s an interesting question. What if Bill Gates threw enough money at, say, lower respiratory infections to eradicate them without trace? What would happen to the millions who would no longer die of pneumonia and the like? Would they live forever? Obviously not.
When a single infectious disease, such as polio, is eradicated, it merely changes the cause of death. A slot is created in the share of death ladder, a new killer enters at the lowest rung, the person dies of something else.
What if one by one, in an amazing world, we eradicated every possible infectious disease? People live disease free, working, contributing to their economies, becoming grandparents.
Waiting for them at the end of the line would be the NCDs—cancer, diabetes, heart disease. These have always dominated the share of death. They are incurable; they are lingering and slow, painful for the affected person and their kin and friends; they require non-stop nursing care sooner or later. They are traumatic for all concerned. And they are costly, for the family and for the government.
Live a short, exuberant life and die quickly of an infectious disease. Or enjoy a long life and die miserably and slowly of an NCD. Nature, it seems, won’t let you have it both ways.
C.Y. Gopinath is a journalist, author, designer and cook who lives in Bangkok